A number of inter and intra-luminal endoscopic procedures require precise placement of anchors or stents. For example, a number of procedures may be performed by entering the gastrointestinal (GI) tract through a first organ or structure, such as the esophagus, stomach, duodenum, small intestine, or large intestine, and delivering the anchor or stent to adjacent organs and lumen or tissue structures such as an adjacent portion of the GI tract, the bile duct, the pancreatic duct, the gallbladder, the pancreas, cysts, pseudocysts, abscesses, and the like. While primarily intended for use in the GI tract, such methods and apparatus can also be used for access to and from portions of the urinary tract, such as the urinary bladder and ureter, the pulmonary tract, such as the trachea and bronchi, and the biliary tract, such as the bile duct and gallbladder, as well.
Intra-ductal stents are commonly used to facilitate the opening of closed vessels for access, drainage or other purposes. Tissue anchors are used to secure adjacent tissues or organs. Inter-luminal tissue anchors, which include a central lumen, are used to facilitate fluid communication between adjacent ducts, organs or lumens. Often, the precise placement of the tissue anchor or stent is necessary, especially when the tissue anchor or stent has well defined anchoring elements at the proximal and/or distal ends, and the device is used to secure adjacent lumens.
When deploying a stent or other tissue anchor between adjacent body lumens, organs, or other structures, it is typically necessary to penetrate both a wall of the first body lumen through which access is established and a wall of a second body lumen which is the target for the procedure. When initially forming such access penetrations, there is a significant risk of leakage from either or both of the access body lumen and the target body lumen into the surrounding space including, but not limited to the peritoneal cavity. In some procedures, such as those involving transgastric or transduodenal bile duct access, loss of body fluid into surrounding tissues and body cavities can present a substantial risk to the patient. The risk can be exacerbated when it is necessary to not only penetrate the luminal walls to gain initial access, usually with a needle, but to subsequently enlarge or dilate the initial penetration, for example by passing a tapered dilator over the needle used to establish initial access. Dilation of the initial tissue penetration can cause additional damage to the tissue penetration and is an additional opportunity for leakage.
Thus, it would be desirable to establish initial luminal wall penetrations and to subsequently dilate said penetrations in order to deploy a stent, anchor, or for other purposes, while minimizing the risk of body fluid leakage. It is also desirable for improved access to body lumens while minimizing trauma and damage to the tissue surrounding the initial luminal wall penetration. It would be further desirable to provide improved protocols and access tools which are capable of being deployed from endoscopes present in a first body lumen to access adjacent body lumens or cavities while minimizing the risk of leakage. Such access tools and protocols should be compatible with a wide variety of procedures, such as placement of stents or other tissue anchors between adjacent luminal walls, and will preferably reduce or eliminate the need to exchange tools during the access procedure.